Method of fabricating containers



May 29, 1945. W, F, ppn-MAN l 2,377,103

METHOD OF FABRICATING CONTAINERS Filed Nov. 23, 1942 Patented May 29,1945 METHOD F FABRICATING CONTAINERS Walter F. Pittman, Huntington Park,Calif., as-

signor to The American Paper Bottle Company, Toledo, Ohio, a corporationof Ohio Application November 23, 1942, Serial No. 466,620

3 Claims.

This invention relates to methods of fabricating containers andparticularly to methods of and apparatus for fabricating papercontainers of the self-supporting type adapted to contain liquids,comprising relatively stiff fiat interconnected panels, and providedwith normally closed pouring openings in the side walls thereof, such asfor instance disclosed in Patent No. 2,218,670 to Racy D. Bennett andPatent No. 2,263,957 to Walter E. Sooy.

In the fabrication of containers of the types disclosed in the patentsreferred to a relatively stiff paper of superior grade is employed andthe container which is ultimately formed from a blank fashioned frompaper of this quality includes a tubular body of rectangular crosssection and a top portion or upper end closure which comprises twoupwardly and inwardly inclined at panels the upper edges of whichterminate in a relatively stiff central rib. Underlying at least one ofthese inclined top panels is a parallel inner -panel and, in these twosuperposed panels there are formed by incisions two registeringopenings, the opening in the outer panel being considerably larger thanthe opening in the inner panel and both openings being normally closedby the tabs deiined by the incisions which form the respective openings,these tabs being secured to each other by an adhesive and being adaptedto be simultaneously lifted, when the outer tab is lifted, swingingabout substantially coincident hinge lines. When lifted in this mannerby one grasping that edge of the outer tab which is remote from thecoincident hinge lines of the two tabs, the pouring opening in the innermember of the two-ply container wall is exposed and there is likewiseexposed a substantial area of theouter face of the inner ply of thecontainer disposed immediately adjacent to the pouring opening.

The relatively large outer tab normally covers and protects againstcontamination both the actual edges of the pouring opening and theoutwardly facing areas of the inner paper panel adjacent the pouringopening, the arrangement being such that the contents of the containermay be readily discharged through the pouring opening provided adjacentits top, by a consumer desiring access and who grasps and lifts, aspreviously explained, that end of the outer tab which is remote from thehinge line, and who there after tilts the container bodily. Accidentaldislocation or opening of the container is prevented by the utilizationof minor uncut portions or bridging elements connecting the edges of theouter tab with the main body of the container, these bridging elementsbeing relatively weak, however, so that they may be readily severed orbroken when the outer tab is deliberately pulled by one desiring accessto the container.

In the usual case containers of the type just above described arefabricated automatically from previously cut blanks on completeautomatic container forming, coating, charging, and sealing machines,the foldable top or upper end portion of the container being acted uponand closed by suitable folding mechanism as the container advances fromstation to station through such machine after having been charged.During the closing operation two opposed panels of the charged tubularcontainer which are ultimately to extend upwardly and inwardly towardthe base of the central rib are angularly deflected through substantialangles during such folding operations. Where the outer of the two tabsof the pouring means is formed wholly from sheet paper incised from atop panel to be deflected the bending over of this top panel has notendency to sever the uncut portions or bridging elements which normallytie the edges of the tab to the body of the panel from which it isformed. It is preferred,

however, to so form the outer tab of the pouring` means that its lowerend, remote from the hinge, iscut from the upper end of the adjacentwall panel and, in this event, the inward deflection of the adjacent toppanel sometimes causes that portion of the tab which is cut from theside panel to break the tying connections -by means of which the end ofthe tab is attached to the remainder of that panel, due to the stiffnessof the paper and its resistance to bending at the scoring defining theupper end of the side panel, any coating material present having atendency to increase the resistance to `bending of the tongue or tab.Naturally the premature dislocation of the lower end of the tongue ishighly undesirable, the projecting end being unprotected and readilycatching on parts of the machine or other article with the result thatthe container may beprematurely opened.

I have discovered that, by treating those portions of the outer or lifttab of the pouring means which are subjected to the folding strains justreferred to during the top closing operation with a gaseous heatingmedium, simultaneously with or just before the application of thefolding forces, the folding operations may be carried out without dangerof severance or rupture of the bridging elements which normally retainthe lower portion of the outer tab of the pouring structure in properposition. The application of the heating medium is particularly helpfulin case the container has, prior to the top folding operation, beencoated with a liquidproof substance such for instance as paraffin andparticularly also in the event that the container has been charged witha chilled substance such as refrigerated milk, the presence of thechilled coating substance upon the surface of the paper impartingincreased stiness to it and giving it an increased tendency to sever thefrangible bridging elements at the free end of the outer tab of thepouring structure.

The period of application of the gaseous heating medium need only bebrief and its effect upon the temperature of the container and itscontents is superficial and transitory only. It should be maintained fora suillcient period, however, to effect the desired result, that is, theapplication of the heat should be maintained for such period as tosoften the coating substance which has been deposited upon the outer tabof the pouring structure and to preferably raise the temperature of theunderlying paper. Various devices may be employed for accomplishing thedesired result, but I preferably make use of a steam jet, the steam jetbeing caused to impinge upon the described surfaces of the container ator just prior to the instant of folding. When this is done the foldingoperation can be performed as rapidly as may be desired and the downwardbending of the upper panel may be continued to any desired angularextent without causing the objectionable detachment of the lower end ofthe outer tab of the pouring structure from the container body.

In the accompanying drawing a container top folding mechanism isillustrated and by successive views of the container the several stepsof the process are indicated.

In the drawing:

Figure l is a tcp plan View of portion of a mechanism for folding andclosing the foldable or collapsible upper end portion of a tubular papercontainer;

Figure 2 is a section on line 2--2 of Figure l;

Figure 3 is a perspective View of a container of the type contemplatedas it appears after having received its coating of liquid-proofingsubstance, and after having been charged with a substance such aschilled milk, but before the relatively foldable panels of its topclosure portion have been finally acted upon to effect the closurethereof;

Figure i is a similar view, the foldable top of the container, however,being shown in a stage considerable further advanced toward closure; and

Figure 5 is a further perspective view of the finally closed and sealedcontainer.

The details of construction of the container are fully disclosed in thepatent to Walter E. Sooy, No. 2,263,957, previously referred to, but itwill be understood that the problem to be dealt with Amay arise inconnection with containers of slightly di'erent type, providing thatthere is present in such container a tab which is cut partially from onepanel of the container and partially from a second panel, these panelsbeing ultimately moved angularly with respect to each other. The body ofthe container is generally indicated by the numeral I0, and is square inhorizontal or cross section. The foldable top portion is indicated bythe numeral I I and this portion includes opposed inwardly collapsiblesections generally indicated at I2 and downwardly foldable opposedsections generally indicated at i3, the downwardly foldable opposedsections i3 including the rectangular panels E3 which ultimately formthe top panels of the gable-like upper end closure of the completedcontainer, and the elongated narrow panels i352 which ultimately formportions of the rib of the completed container.

It is not necessary to further describe in detail the variousadvantageous features of the container other than to say that, after ithas been finally closed and sealed or has reached the condition in whichit is shown in Figure 5, it is transmitted to a consumer who, when hedesires access to its contents, lifts or grasps the lower end T of thelift tab T and pulls this lower end outwardly and upwardly, severing theminor relatively weak bridging elements I4 which are the sole means formaintaining the lower end T of the lift tab T in the plane of the sidepanel Ill of the body, the lift tab T being formed in part in top panelI3 and in part in side panel Ill' and being adapted to be swung upwardlyand outwardly in the container opening operation about the scoredconnecting or hinge portion I5 at the top of the lift tab. As the tab islifted and swung upwardly about the hinge line I5 it also lifts andcarries with it the inner tab i6, formed in an inner ply of thecontainer or panel directly underlying, contacting with and secured tothe inclined panel I3', and at least the upper part of panel I0',displacement of the inner tab I6 uncovering a pouring opening formed inthis inner ply, through which the liquid contents of the container willflow when the container is suitably tilted, al1 as disclosed in theprior patents referred to, the two-ply construction being shownparticularly in the previously mentioned Sooy patent. By comparing l theangular relationship of panels I3 and lil' in Figures 3 and 5, it willbe observed that the angularity of these two panels is verysubstantially increased during the top closing operation.

In Figure 2, in which panel I3' is shown in an intermediate position,there is diagrammatically illustrated means Il for directing a jet ofsteam ll against the side surface of the container and particularlyagainst the lift tab T and those portions Of the container adjacent thelift tab. The e'ect of this is to soften the coating materialtemporarily and permit the relative folding movement of the top and sidewall panels to proceed freely withoutY danger of breakage or rupture ofthe tying or bridging elements Id previously referred to. Theapplication of the heating jet is only continued so long as necessary toachieve the desired result, which is very quickly attained, and hencethe softened coating substance resumes its original state or conditionalmost immediately after the completion of the folding operation.

While the invention may be used with great advantage in the treatment,during folding, of containers the walls of which are one ply only inthickness it is particularly helpful in the fabrication of containers inwhich the outer and inner tabs of the pouring device are formed,respectively, in separate plies of relatively stiff paper and where, asa preliminary step7 the paper hasI been coated and at least partiallyimpregnated with a parain-like substance which is relatively stili whenin a solid state. Steam applied to such a container, in the manner andover the area indicated in the drawing, has the effect not only ofsoftening the surface coating, but also of softening the paraflin whichhas been absorbed by the fibers of the paper. Melting of the parafiinresults in softening of the fibers of the paper itself, with the resultthat the two-ply wall of the container is momentarily rendered quiteflexible, thus greatly facilitating folding by reducing stress betweenthe paper plies during the folding operation.

As a result no great amount of tension in the outer ply is caused by thebending of the paper wall and but little strain imposed on the bridgingelements. Likewise the incisions intermediate the bridging elements I4will not be enlarged by the stretching of such elements. Ordinarily,when the gaseous heating medium is not employedr the relatively hard andbrittle paraffin in these incisions tends to break during folding,increasing the likelihood of leakage. The application of steam in thespecified manner averts this danger.

In Figure 1 of the drawing, and likewise in Figure 2, a foldingmechanism is disclosed, the details of which may be readily perceivedfrom an inspection of Patent No. 2,156,037, issued to J. E. Wollenweber,.April 25, 1939, and need not be herein particularly described. In theseviews also, there is disclosed a means for conducting steam to theproximity of the container against which the steam jet is to bedirected, this means comprising the duct terminating at 2| a, shortdistance from the side of that container shown in position B in Figure1, and indicated in chain lines. The container top folding meansincludes stationary cam elements three of which are indicated at 22, 23and 24 in the drawing and a conveyor, portions of which are shown inFigure 2, including a supporting member 25 upon which the containersrest as they are moved past the folding means, portions of the containeradvancing mechanism being indicated diagrammatically at 26 and 21,respectively. As the containers advance past the top closing mechanism,in the direction indicated by the arrow D in Figure 1 the stationaryblades or cams 22, 23 and 24 affect the folding operations in the mannerfully described in the Wollenweber patent referred to, chargedcontainers substantially in the condition indicated in Figure 3 enteringthe closing mechanism from the right (Figure 1) and issuing from theclosing mechanism substantially in the condition shown in Figure 5,ready for the application of the final sealing pressure to the rib andthe insertion of a securing staple. During the folding operation thecurrent of heating medium is applied in the manner previously describedand the folding operation is so facilitated that the bending or foldingof the previously incised lift tab T, along the intermediate scoring tfreely proceeds without danger of rupture of the bridging elements I4.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. The method of fabricating containers which comprises forming a paperblank having an access tab defined by incisions, the tab comprisingportions of two adjacent relatively foldable panels with one endhingedly connected to one panel and the other end connected to the otherpanel by relatively weak bridging elements, coating the blank with aliquid-proofing substance which is solid at ordinary temperatures andplastic at higher temperatures directing a current of a gaseous heatingmedium against the tab to soften the coating thereon and while thecoating is in softened condition, relatively folding the panels and atthe same time bending the tab intermediate its ends.

2. The method of fabricating containers which comprises forming a paperblank having an access tab defined by incisions, the tab comprisingportions of two adjacent relatively foldable panels with one endhingedly connected to one panel and the other end connected to the otherpanel by relatively weak bridging elements, coating the blank with aliquid-proofing substance which is solid at ordinary temperatures andplastic at, higher temperatures, partially folding the coated blankalong a scored portion intersecting the tab, directing a gaseous heatingmedium against said scored portion of the tab and, while the coating isin plastic condition, effecting further folding o the said panelsrelatively to each other.

3. The method set forth in claim 1 in which the container is chargedwith a body of chilled liquid prior to the application of the current ofgaseous heating medium, and the heating medium is supplied in suflicientvolume and at suiliciently high temperature to soften the coating of thecharged container.

WALTER F. PIITMAN.

